Hacksjön
Encyclopedia
Hacksjön is a small lake
located east of the former airport at Tullinge
, in the municipality Botkyrka in southern Stockholm
, Sweden
. It forms the westernmost lake of one of the branches of the Tyresån lake system and is located within the Lida-Riksten Open-air Area.
With its isolated location surrounded by moorland
s and forests, the lake remains relatively unaffected by human activities, which is mostly limited to precipitation and incoming nutrients from local soil. The lake is used for wireless radio-controlled boat
s in summers and for ice racing
in winters, which have reduced the previously prominent bird life by the lake. Notwithstanding, it is classified as of considerable importance for nature conservation.
and a shooting range
.
In a 2002 key plan, the land surrounding the lake, owned by the city of Stockholm, is indented to be transformed into one of three nature reserve
within the Lida-Riksten Open-air Area forming one of the important green wedges
of Stockholm. Encompassing 240 hectares, it is marked as "conservation of rural area" and "larger area valuable for open-air life". Additionally, the area is considered as of significant archaeological interest since it 8.000 years ago, during the Stone Age
, was an archipelago composed of sparsely scattered islands and thus contains many traces of the earliest settlements in Stockholm. The area between the lake and the golf course south of it is considered as of great importance for social history since the homestead there is believed to be about 1.500 years old.
of 7,3, the lake is unlikely to acidified.
s thriving in the shallow lake include Bladderwort
, Common Club-rush
, and Water Lilies
. The quagmire bordering the lake, dominated by Peat Moss
and Reed
, also include sedges
, Marsh Willowherb
, Common Marsh Bedstraw
, Mare's Tail
, Gypsywort
, Bog-myrtle
, White Water-lily
, Milk Parsley
, Broad-leaved Pondweed
, Marsh Cinquefoil
, Grey Sallow
, Common Club-rush
, Bur-reed
, Narrow Leaf Cattail
, and Broadleaf Cattail
.
Open-air and motor sport activities have driven away a range of birds species once abundant by the lake, including the colony of Black-headed Gull
which once dominated it, other common species such as Pochard
, Common Teal
, Mute Swan
, Eurasian Coot
, and more rare visitors such as Osprey
, Black-throated Diver
.
Fry of Smooth Newt
was reported in 2000, the only amphibian
reported by the lake. An inventory of damselflies in 1997 resulted in a list of Emerald Damselfly, Red-eyed Damselfly
, Variable Damselfly
, Southern Hawker
, Brilliant Emerald
, Four-spotted Chaser
, Eastern White-faced Darter, and Black Darter
. A second inventory in 2000 produced the following list interpreted as a normal amount of species: Common Hawker
, Brown Hawker
, Irish Damselfly
, Variable Damselfly, Downy Emerald
, Red-eyed Damselfly, Northern White-faced Darter, Brilliant Emerald, and Black Darter.
Lake
A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...
located east of the former airport at Tullinge
Tullinge
Tullinge is a suburb of Greater Stockholm, Sweden. It is located in the eastern part of Botkyrka Municipality, on the border to the Flemingsberg part of Huddinge Municipality.Tullinge has become known for the Airforce airfield , now closed down....
, in the municipality Botkyrka in southern Stockholm
Stockholm
Stockholm is the capital and the largest city of Sweden and constitutes the most populated urban area in Scandinavia. Stockholm is the most populous city in Sweden, with a population of 851,155 in the municipality , 1.37 million in the urban area , and around 2.1 million in the metropolitan area...
, Sweden
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
. It forms the westernmost lake of one of the branches of the Tyresån lake system and is located within the Lida-Riksten Open-air Area.
With its isolated location surrounded by moorland
Moorland
Moorland or moor is a type of habitat, in the temperate grasslands, savannas, and shrublands biome, found in upland areas, characterised by low-growing vegetation on acidic soils and heavy fog...
s and forests, the lake remains relatively unaffected by human activities, which is mostly limited to precipitation and incoming nutrients from local soil. The lake is used for wireless radio-controlled boat
Radio-controlled boat
- Fun Sport :Electric Sport boats are the most common type of boat amongst casual hobbyists. Hobby quality boat speed generally start at around 20MPH and go up from there, and can be just as fast or faster than their internal combustion counterparts, with the latest in Lithium Polymer and Brushless...
s in summers and for ice racing
Ice racing
Ice racing is a form of racing that uses cars, motorcycles, snowmobiles, All-terrain vehicles, or other motorized vehicles. Ice racing takes place on frozen lakes or rivers, or on carefully groomed frozen lots...
in winters, which have reduced the previously prominent bird life by the lake. Notwithstanding, it is classified as of considerable importance for nature conservation.
Catchment area
The lake is located in a marshy moorland surrounded by forests. West of it is a former military airport today used for motocrossMotocross
Motocross is a form of motorcycle sport or all-terrain vehicle racing held on enclosed off road circuits. It evolved from trials, and was called scrambles, and later motocross, combining the French moto with cross-country...
and a shooting range
Shooting range
A shooting range or firing range is a specialized facility designed for firearms practice. Each facility is typically overseen by one or more supervisory personnel, called variously a range master or "RSO – Range Safety Officer" in the United States or a range conducting officer or "RCO" in the UK...
.
In a 2002 key plan, the land surrounding the lake, owned by the city of Stockholm, is indented to be transformed into one of three nature reserve
Nature reserve
A nature reserve is a protected area of importance for wildlife, flora, fauna or features of geological or other special interest, which is reserved and managed for conservation and to provide special opportunities for study or research...
within the Lida-Riksten Open-air Area forming one of the important green wedges
Green belt
A green belt or greenbelt is a policy and land use designation used in land use planning to retain areas of largely undeveloped, wild, or agricultural land surrounding or neighbouring urban areas. Similar concepts are greenways or green wedges which have a linear character and may run through an...
of Stockholm. Encompassing 240 hectares, it is marked as "conservation of rural area" and "larger area valuable for open-air life". Additionally, the area is considered as of significant archaeological interest since it 8.000 years ago, during the Stone Age
Stone Age
The Stone Age is a broad prehistoric period, lasting about 2.5 million years , during which humans and their predecessor species in the genus Homo, as well as the earlier partly contemporary genera Australopithecus and Paranthropus, widely used exclusively stone as their hard material in the...
, was an archipelago composed of sparsely scattered islands and thus contains many traces of the earliest settlements in Stockholm. The area between the lake and the golf course south of it is considered as of great importance for social history since the homestead there is believed to be about 1.500 years old.
Environmental influence
The shallow lake is moderately rich in nutrients and virtually unaffected by pollution. Additionally, it is rich in humus which gives the water its dark brown colour. With a pHPH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...
of 7,3, the lake is unlikely to acidified.
Flora and fauna
Aquatic plantAquatic plant
Aquatic plants are plants that have adapted to living in aquatic environments. They are also referred to as hydrophytes or aquatic macrophytes. These plants require special adaptations for living submerged in water, or at the water's surface. Aquatic plants can only grow in water or in soil that is...
s thriving in the shallow lake include Bladderwort
Bladderwort
Utricularia, commonly and collectively called the bladderworts, is a genus of carnivorous plants consisting of approximately 233 species . They occur in fresh water and wet soil as terrestrial or aquatic species across every continent except Antarctica...
, Common Club-rush
Scirpus
The plant genus Scirpus consists of a large number of aquatic, grass-like species in the family Cyperaceae , many with the common names club-rush or bulrush . Other common names are deergrass or grassweed.The genus has a cosmopolitan distribution, and grows in wetlands and moist soil...
, and Water Lilies
Nymphaeaceae
Nymphaeaceae is a family of flowering plants. Members of this family are commonly called water lilies and live in freshwater areas in temperate and tropical climates around the world. The family contains eight genera. There are about 70 species of water lilies around the world. The genus...
. The quagmire bordering the lake, dominated by Peat Moss
Sphagnum
Sphagnum is a genus of between 151 and 350 species of mosses commonly called peat moss, due to its prevalence in peat bogs and mires. A distinction is made between sphagnum moss, the live moss growing on top of a peat bog on one hand, and sphagnum peat moss or sphagnum peat on the other, the...
and Reed
Phragmites
Phragmites, the Common reed, is a large perennial grass found in wetlands throughout temperate and tropical regions of the world. Phragmites australis is sometimes regarded as the sole species of the genus Phragmites, though some botanists divide Phragmites australis into three or four species...
, also include sedges
Carex
Carex is a genus of plants in the family Cyperaceae, commonly known as sedges. Other members of the Cyperaceae family are also called sedges, however those of genus Carex may be called "true" sedges, and it is the most species-rich genus in the family. The study of Carex is known as...
, Marsh Willowherb
Epilobium
Epilobium is a genus in the family Onagraceae, containing about 160-200 species of flowering plants with a worldwide distribution. They are generally abundant in the subarctic, temperate and subantarctic regions, whereas in the subtropics and tropics they are restricted to the cool montane biomes,...
, Common Marsh Bedstraw
Galium
Galium is a large genus of annual and perennial herbaceous plants in the family Rubiaceae, with 617 known species occurring in the temperate zones of both the Northern and Southern Hemispheres. Most species are known as bedstraw. G...
, Mare's Tail
Common Mare's Tail
The Common Mare's tail, Hippuris vulgaris, is a common aquatic plant of Eurasia and North America.The species is also sometimes called Horsetail, a name which is better reserved to the Horsetails of genus Equisetum...
, Gypsywort
Gypsywort
Lycopus europaeus is a perennial plant in the Lycopus genus, native to Europe and Asia, and naturalized in the United States.-Habitat:...
, Bog-myrtle
Myrica gale
Myrica gale is a species of flowering plant in the genus Myrica, native to northern and western Europe and parts of northern North America. It is a deciduous shrub growing to 1–2 m tall. Common names include Bog Myrtle and Sweet Gale...
, White Water-lily
Nymphaea alba
Nymphaea alba, also known as the European White Waterlily, White Lotus, or Nenuphar, is an aquatic flowering plant of the family Nymphaeaceae....
, Milk Parsley
Milk Parsley
Milk Parsley is a plant in the family Apiaceae. Also known as Marsh Hog's Fennel.It resides on wetlands, mires etc., shallow riverbanks, occasionally on ditches and other smaller water features. It's relatively shadow-tolerant. It requires seasonal submerging of the site to compete with other...
, Broad-leaved Pondweed
Potamogeton
Potamogeton is a genus of aquatic, mostly freshwater, plants of the family Potamogetonaceae. Most are known by the common name pondweed, although many unrelated plants may be called pondweed, such as Canadian pondweed...
, Marsh Cinquefoil
Potentilla
Potentilla is the genus of typical cinquefoils, containing about 500 species of annual, biennial and perennial herbs in the rose family Rosaceae. They are generally Holarctic in distribution, though some may even be found in montane biomes of the New Guinea Highlands...
, Grey Sallow
Grey Sallow
Salix cinerea is a species of willow native to Europe and western Asia.It is a deciduous shrub or small tree growing to 4-15 m high. The leaves are spirally arranged, 2–9 cm long and 1–3 cm broad , green above, hairy below, with a crenate margin...
, Common Club-rush
Scirpus
The plant genus Scirpus consists of a large number of aquatic, grass-like species in the family Cyperaceae , many with the common names club-rush or bulrush . Other common names are deergrass or grassweed.The genus has a cosmopolitan distribution, and grows in wetlands and moist soil...
, Bur-reed
Sparganium
Sparganium is a genus of flowering plants, containing about 20 species in temperate regions of both the Northern and Southern Hemispheres. It was previously placed alone in the family Sparganiaceae...
, Narrow Leaf Cattail
Typha angustifolia
Typha angustifolia L., , is a perennial herbaceous plant of genus Typha. This cattail is an "obligate wetland" species that is commonly found in the northern hemisphere in brackish locations...
, and Broadleaf Cattail
Typha latifolia
Typha latifolia is a perennial herbaceous plant in the genus Typha. It is found as a native plant species in North and South America, Europe, Eurasia, and Africa...
.
Open-air and motor sport activities have driven away a range of birds species once abundant by the lake, including the colony of Black-headed Gull
Black-headed Gull
The Black-headed Gull is a small gull which breeds in much of Europe and Asia, and also in coastal eastern Canada. Most of the population is migratory, wintering further south, but some birds in the milder westernmost areas of Europe are resident...
which once dominated it, other common species such as Pochard
Pochard
The Common Pochard, Aythya ferina, is a medium-sized diving duck.The adult male has a long dark bill with a grey band, a red head and neck, a black breast, red eyes and a grey back. The adult female has a brown head and body and a narrower grey bill band. The triangular head shape is distinctive...
, Common Teal
Common Teal
The Eurasian Teal or Common Teal is a common and widespread duck which breeds in temperate Eurasia and migrates south in winter. The Eurasian Teal is often called simply the Teal due to being the only one of these small dabbling ducks in much of its range...
, Mute Swan
Mute Swan
The Mute Swan is a species of swan, and thus a member of the duck, goose and swan family Anatidae. It is native to much of Europe and Asia, and the far north of Africa. It is also an introduced species in North America, Australasia and southern Africa. The name 'mute' derives from it being less...
, Eurasian Coot
Eurasian Coot
The Eurasian Coot, Fulica atra, also known as Coot, is a member of the rail and crake bird family, the Rallidae. The Australian subspecies is known as the Australian Coot.-Distribution:...
, and more rare visitors such as Osprey
Osprey
The Osprey , sometimes known as the sea hawk or fish eagle, is a diurnal, fish-eating bird of prey. It is a large raptor, reaching more than in length and across the wings...
, Black-throated Diver
Black-throated Diver
The Black-throated Loon is a migratory aquatic bird found in the northern hemisphere. The species is known as an Arctic Loon in North America and the Black-throated Diver in Eurasia, its current name is a compromise proposed by the International Ornithological Committee.-Taxonomy:The...
.
Fry of Smooth Newt
Smooth Newt
The Smooth Newt, also known as the Common Newt, Lissotriton vulgaris is the most common newt species of the Lissotriton genus of amphibians. L...
was reported in 2000, the only amphibian
Amphibian
Amphibians , are a class of vertebrate animals including animals such as toads, frogs, caecilians, and salamanders. They are characterized as non-amniote ectothermic tetrapods...
reported by the lake. An inventory of damselflies in 1997 resulted in a list of Emerald Damselfly, Red-eyed Damselfly
Red-eyed Damselfly
Red-eyed Damselfly Erythromma najas is a member of the damselfly family Coenagrionidae.-Appearance:The species is a small damselfly, long, predominantly black with iridescent blue markings. The male resembles blue-tailed damselflies but is distinguished by its large, spaced eyes that are a deep red...
, Variable Damselfly
Variable Damselfly
Coenagrion pulchellum, the Variable Damselfly or Variable Bluet, is a European damselfly. Despite its name, it is not the only blue damselfly prone to variable patterning....
, Southern Hawker
Southern Hawker
The Southern Hawker or Blue Darner is a long species of hawker dragonfly.It is large, with a long body. It has green markings on the black bodies, and the male also has blue spots on the abdomen....
, Brilliant Emerald
Brilliant Emerald
The Brilliant Emerald, Somatochlora metallica, is a middle-sized species of dragonfly. It is the largest and greenest of the Somatochlora species; long....
, Four-spotted Chaser
Four-spotted Chaser
The Four-spotted Chaser , known in North America as the Four-spotted Skimmer, is a dragonfly of the family Libellulidae found frequently throughout Europe, Asia, and North America....
, Eastern White-faced Darter, and Black Darter
Black Darter
The Black Darter or Black Meadowhawk is a dragonfly found in northern Europe, Asia, and North America. At about 30 mm long, it is Britain's smallest resident dragonfly...
. A second inventory in 2000 produced the following list interpreted as a normal amount of species: Common Hawker
Common Hawker
The Common Hawker or Sedge Darner is one of the larger species of hawker dragonflies. It is native to Eurasia and northern North America. The flight period is from June to early October.It is long with a brown body...
, Brown Hawker
Brown Hawker
The Brown Hawker is a large dragonfly about long. It is a distinctive species and is easily recognised, even in flight, by its brown body and bronze wings...
, Irish Damselfly
Irish Damselfly
The Irish Damselfly or Crescent Bluet is a damselfly found in northern Europe; outside northern Finland the species is rare. It is also scarce and local in the Netherlands and Ireland. One of its English name comes from the fact that it is found in Ireland but not in Britain...
, Variable Damselfly, Downy Emerald
Downy Emerald
The downy emerald is a species of dragonfly. It is metallic green and bronze in color, and its thorax is coated with fine hairs, hence its name. Like most other emeralds, the downy emerald has bright shiny green eyes...
, Red-eyed Damselfly, Northern White-faced Darter, Brilliant Emerald, and Black Darter.